Page 109 - JavaScript

function deepReverse(arr) {
arr.reverse().forEach(elem => {
if(Array.isArray(elem)) {
deepReverse(elem);
}
});
return arr;
}

Example for deepReverse:

var arr = [1, 2, 3, [1, 2, 3, ['a', 'b', 'c']]];

deepReverse(arr);

Results in:

arr // -> [[['c','b','a'], 3, 2, 1], 3, 2, 1]

Remove value from array

When you need to remove a specific value from an array, you can use the following one-liner to
create a copy array without the given value:

array.filter(function(val) { return val !== to_remove; });

Or if you want to change the array itself without creating a copy (for example if you write a function
that get an array as a function and manipulates it) you can use this snippet:

while(index = array.indexOf(3) !== -1) { array.splice(index, 1); }

And if you need to remove just the first value found, remove the while loop:

var index = array.indexOf(to_remove);
if(index !== -1) { array.splice(index , 1); }

Checking if an object is an Array

Array.isArray(obj) returns true if the object is an Array, otherwise false.

Array.isArray([]) // true
Array.isArray([1, 2, 3]) // true
Array.isArray({}) // false
Array.isArray(1) // false

In most cases you can instanceof to check if an object is an Array.

[] instanceof Array; // true
{} instanceof Array; // false

https://riptutorial.com/ 66